Apparatus for Locating a Mobile Railway Asset

ABSTRACT

In one aspect of the present disclosure, an apparatus for locating a mobile railway asset is provided that includes a power source, GNSS circuitry configured to utilize electrical power from the power source to receive GNSS data, and a controller operatively coupled to the power source and the GNSS circuitry. The controller has a power saving mode wherein the controller inhibits the GNSS circuitry from receiving GNSS data and a standard accuracy mode wherein the controller permits the GNSS circuitry to receive GNSS data for a first time period. The controller has a higher accuracy mode wherein the controller permits the GNSS circuitry to receive GNSS data for a second time period longer than the first time period, and subsequently across multiple instances, in order to collect more GNSS data that can be qualified, filtered, sorted, and averaged to produce a more accurate result.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.16/868,523, filed May 6, 2020, which claims the benefit of U.S.Provisional Patent Application No. 62/845,098, filed May 8, 2019, whichare hereby incorporated by reference in their entireties.

FIELD

This disclosure relates to global navigation satellite system(GNSS)-enabled devices having limited powered sources and, morespecifically, to GNSS-enabled devices for use with mobile railwayassets. Mobile railway assets may include, for example, locomotives,railcars, containers, and/or rail maintenance equipment.

BACKGROUND

Each satellite of a GNSS constellation periodically transmits a signalcontaining GNSS data including ephemeris data and timing data for all ofthe satellites of the GNSS constellation. The GNSS satellites each havea time slot to transmit their information. It may take around 10-12seconds for all the satellites of a GNSS constellation to broadcasttheir GNSS data. The ephemeris data includes the position of thesatellites of the GNSS constellation and orbital characteristics of thesatellites. A GNSS-enabled device has a GNSS receiver, such as achipset, that receives the GNSS data from GNSS satellites visible to theGNSS-enabled device. The GNSS receiver uses the GNSS data and the timethe GNSS receiver received the GNSS data from the visible GNSSsatellites to calculate a position of the chipset on earth.

Conventional GNSS-enabled devices that are designed to be used in railapplications often have limited accuracy due to the power constraintsplaced on GNSS operation in order to preserve the power source of thedevice. These power sources may include a primary battery, which is notrechargeable, or a rechargeable battery. Another type of power sourceused in some GNSS-enabled devices includes a super-capacitor inconjunction with a battery and/or an energy harvesting mechanism thatgenerates electrical energy from the movement of the mobile railwayasset.

The limited accuracy provided by conventional GNSS-enabled devices isdue to the power demands of a GNSS receiver of the device. Morespecifically, the GNSS receiver of a battery powered GNSS-enabled devicetypically consumes a large amount of power when collecting andprocessing GNSS data, which includes ephemeris data and timing data(e.g. clock pulses), from orbiting satellites of a GNSS constellation todetermine the location of the device on Earth. The ephemeris data maycontain satellite accuracy and health information, clock correctioncoefficients, and/or orbital parameters to determine the preciselocation of each satellite in orbit. Each satellite transmits this dataon a periodic interval, so that GNSS receivers can have up-to-date datafor the satellites used for calculating location.

Collecting ephemeris data and timing data from the satellites requirespower. As such, any time when the GNSS receiver is powered, the GNSSreceiver decreases the amount of energy stored in the battery of theGNSS-enabled device. And, the less frequently the GNSS receiver isenergized or powered, the less accurate the determined location will be,because there may be fewer satellites available in the sky from which tocollect ephemeris data and the accuracy of ephemeris data may decay.Therefore, a balance must be struck between the energy consumed by theGNSS-enabled device and the accuracy of the GNSS location datadetermined by the device.

One prior approach involves operating a GNSS receiver of a batterypowered GNSS-enabled device mounted to a railcar according to apredetermined schedule. The relatively infrequent operation of the GNSSreceiver called for by the schedule may be sufficient for determiningrailcar location when the railcar is traveling along a railroad track.The GNSS-enabled device has an accelerometer to detect a sudden changeof speed of the railcar, such as the railcar coming to rest in a railyard. The GNSS-enabled device operates the GNSS receiver in response tothe sudden change of speed to determine the railcar location. This priorapproach thereby balanced battery consumption and accuracy by operatingthe GNSS receiver infrequently when precise railcar location informationwas not required and operating the GNSS receiver more frequently when anexternal event, e.g., coming to rest in a rail yard, indicates moreaccurate location information may be desired.

SUMMARY

In accordance with one aspect of the present disclosure, an apparatus isprovided for locating a mobile railway asset. The apparatus includes alimited power source and global navigation satellite system (GNSS)circuitry configured to utilize electrical power from the power sourceto receive GNSS data from satellites of a GNSS constellation. The GNSSdata includes ephemeris data representative of the satellites in spaceand timing data from the satellites. The term satellite or GNSSsatellite as used herein is intended to refer to a satellite of a GNSSconstellation. The satellite(s) may provide functionality in addition toproviding GNSS data, such as detecting a nuclear detonation.

The apparatus also includes a controller operatively coupled to thelimited power source and the GNSS circuitry. The controller has a powersaving mode wherein the controller inhibits the GNSS circuitry fromreceiving GNSS data and a standard accuracy mode wherein the controllerpermits the GNSS circuitry to receive GNSS data for a first time period.The controller also has a higher accuracy mode wherein the controllerpermits the GNSS circuitry to receive GNSS data for a second time periodlonger than the first time period. The controller is configured to enterthe higher accuracy mode and permit the GNSS circuitry to receive GNSSdata for the second time period in response to a determination of amobile railway asset event. The apparatus further includes communicationcircuitry operatively coupled to the controller and configured tocommunicate data indicative of a location of the mobile railway assetbased at least in part on the GNSS data received during the longersecond time period. It has been discovered that the accuracy of receivedGNSS data generally increases when the receiver is active long enough toreceive updated GNSS data containing the most up-to-date positionalaccuracy data from each satellite. Because the GNSS circuitry canoperate for the longer second time period, the GNSS circuitry utilizesmore visible satellites in the constellation with more precise GNSSdata, which permits a more accurate determination of the location of themobile railway asset. This ability to operate in the standard accuracymode and the higher accuracy mode permits less stored energy from thepower source to be used in the standard accuracy mode when a lessaccurate location determination is required, such as when the mobilerailway asset is in transit, and more stored energy to be used in thehigher accuracy mode when a more accurate location determination isrequired, such as when the mobile railway asset is in a rail yard.

The controller may perform operations on the received GNSS data toimprove accuracy. For example, when a mobile railway asset associatedwith the apparatus is known to be stationary, multiple locationcalculations may be performed using GNSS data received during separateperiods of time and averaged together to provide a more accurateresolution of position because many different satellites would be used,at different elevations and angles.

In another aspect, a system is provided including a mobile railwayasset, a limited power source, and global navigation satellite system(GNSS) circuitry configured to utilize electrical power from the powersource to receive GNSS data from satellites of a GNSS constellation. Themobile railway asset may be, for example, a locomotive, a railcar, arail maintenance vehicle, a container(s), and/or a crane. The systemincludes a controller having a power saving mode wherein the controllerinhibits the GNSS circuitry from receiving GNSS data and a standardaccuracy mode wherein the controller permits the GNSS circuitry toreceive GNSS data for a first time period. The controller further has ahigher accuracy mode wherein the controller permits the GNSS circuitryto receive GNSS data for a second time period longer than the first timeperiod. The controller is configured to enter the higher accuracy modeand permit the GNSS circuitry to receive GNSS data for the second timeperiod in response to a determination of a mobile railway asset event.The system includes communication circuitry operatively coupled to thecontroller and configured to communicate data indicative of a locationof the mobile railway asset based at least in part on the GNSS datareceived during the second time period. The standard accuracy mode maybe utilized to provide periodic updates of the location of the mobilerailway asset according to a set schedule or particular events. Thehigher accuracy mode may be utilized only sporadically when a higheraccuracy location determination is required. The controller therebybalances preserving stored energy of the power source by using thestandard accuracy mode for less-critical location determinations whileconsuming more stored energy as needed for higher location accuracy inthe higher accuracy mode.

The present disclosure also provides a method of operating a sensingapparatus for a mobile railway asset. The method includes, at thesensing apparatus, inhibiting global navigation satellite system (GNSS)circuitry of the sensing apparatus from receiving GNSS data fromsatellites of a GNSS to conserve stored energy of a limited power sourceof the apparatus. The method includes permitting the GNSS circuitry toreceive GNSS data for a first time period and wirelessly transmittingdata indicative of a location of the mobile railway asset based at leastin part on the GNSS data received during the first time period. Themethod further includes in response to a determination of a mobilerailway asset event, permitting the GNSS circuitry to receive GNSS datafor a second time period longer than the first time period. The methodfurther includes wirelessly transmitting data indicative of a locationof the mobile railway asset based at least in part on the GNSS datareceived during the second time period from communication circuitry ofthe sensory apparatus. In this manner, the method permits a moreaccurate determination of the mobile railway asset location using theGNSS data received during the longer second time period and in responseto a determination of a mobile railway asset event. The longer secondtime period permits the GNSS circuitry to obtain more GNSS data, andpotentially from a greater number of visible satellites, than the firsttime period, which results in more accurate location determination forthe mobile railway asset.

In another aspect of the present disclosure, a stationary gateway isprovided for facilitating monitoring of the location of a mobile railwayasset in a railway connected facility. The railway connected facilitymay be, for example, a rail yard of a railroad, a rail yard of aproduction company, or a train station. The stationary gateway includesa GNSS receiver configured to receive GNSS data from satellites of aGNSS and a communication interface operable to communicate with aGNSS-enabled device of a mobile railway asset, the communicationinterface configured to facilitate communication between theGNSS-enabled device and a remote computer over a network. The stationarygateway further includes a processor operably coupled to the GNSSreceiver and the communication interface. The processor is configured toperform a self-survey using the GNSS data from the GNSS receiver anddetermine a self-surveyed location of the stationary gateway.

In one embodiment, the self-survey involves the processor calculatingmultiple location fixes for the stationary gateway over an extendedperiod, such as greater than 24 hours, using data from all or asubstantial portion of the satellites of a GNSS. A location fixgenerally includes a latitude, longitude, altitude, and time coordinateof the GNSS receiver. The processor performs an averaging algorithm onthe multiple location fixes to accurately determine a self-surveyedlocation of the stationary gateway.

The processor is further configured to determine a current location ofthe stationary gateway using current GNSS data received by the GNSSreceiver wherein the current location of the stationary gateway isdetermined with less accuracy than the self-surveyed location. Thecurrent location determination is less accurate than the self-surveyedlocation due at least in part to the shorter time period for gatheringlocation data from satellites of the GNSS to determine the currentlocation than the self-surveyed location.

The processor is configured to determine current location error data bycomparing the current location of the stationary gateway to theself-surveyed location of the stationary gateway. Still further, theprocessor of the stationary gateway is configured to communicate thecurrent location error data to the GNSS-enabled device to facilitate theGNSS-enabled device determining a location of the mobile railway assetbased at least in part on current location error data from thestationary gateway. In this manner, the location of the mobile railwayasset may be determined in a highly accurate manner using error datafrom the stationary gateway rather than relying solely on the GNSS datareceived by the GNSS-enabled device. This permits the GNSS-enableddevice to operate the GNSS circuitry thereof for shorter periods of timeand preserve the limited power source of the GNSS-enabled device.

The disclosure also provides an apparatus for monitoring the location ofa mobile railway asset. The apparatus includes a limited power sourceand GNSS circuitry configured to utilize electrical power from thelimited power source to receive GNSS data from the satellites of a GNSS.The apparatus further includes communication circuitry configured towirelessly receive current location error data from a stationarygateway. The current location error data is determined by comparingcurrent location data of the stationary gateway to a self-surveyedlocation of the stationary gateway. The apparatus also includes acontroller operatively connected to the GNSS circuitry and thecommunication circuitry. The controller has a power saving mode whereinthe controller inhibits the GNSS circuitry from receiving GNSS data anda location mode wherein the controller permits the GNSS circuitry toreceive GNSS data. The controller is configured to determine a locationof the mobile railway asset based at last in part on the received GNSSdata and the current location error data from the stationary gateway.The controller may thereby determine a location of the mobile railwayasset with high accuracy while minimizing power consumption associatedwith operation of the GNSS circuitry.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a train consist including a locomotivehaving a powered wireless gateway and mobile railway assets havingcommunication management units such as GNSS-enabled devices and wirelesssensor nodes;

FIG. 1B is a perspective view of one of the mobile railway assets ofFIG. 1A having a GNSS-enabled device and wireless sensor nodes;

FIG. 2 is a system block diagram of the GNSS-enabled device of FIG. 1B;

FIG. 3 is a flow chart showing a method of operating the GNSS-enableddevice of FIG. 2 ;

FIG. 4 is a flow chart of a method for calculating the location of themobile railway asset using the GNSS-enabled device of FIG. 2 ;

FIG. 5 is a comparison of the GNSS location accuracy provided by theGNSS-enabled device of FIG. 2 in a standard accuracy mode (R¹) and ahigher accuracy mode (R²);

FIG. 6 is a schematic representation of a system implementingGNSS-enabled devices according to the present disclosure;

FIG. 7 is a schematic representation of a system for monitoring thelocation of a mobile railway asset;

FIG. 8 is a block diagram of a stationary gateway of the system of FIG.7 ;

FIG. 9 is a flow chart showing a method of locating a rail car using thestationary gateway of FIG. 8 ;

FIGS. 10A and 10B are schematic representations of the satellitesvisible to the GNSS-enabled device of FIG. 1B;

FIG. 11 is a schematic representation of the stationary gateway of FIG.8 receiving GNSS data from a greater number of satellites than theGNSS-enabled device of a mobile railway asset due to a buildingobstructing the GNSS-enabled device; and

FIG. 12 is a schematic representation of a rail yard having stationarygateways of FIG. 8 for communicating GNSS error data to GNSS-enableddevices of mobile railway assets in the rail yard.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions and/or relative positioningof some of the elements in the figures may be exaggerated relative toother elements to help to improve understanding of various embodimentsof the present invention. Also, common but well-understood elements thatare useful or necessary in a commercially feasible embodiment are oftennot depicted to facilitate a less obstructed view of these variousembodiments. It will further be appreciated that certain actions and/orsteps may be described or depicted in a particular order of occurrencewhile those skilled in the art will understand that such specificitywith respect to sequence is not actually required. It will also beunderstood that the terms and expressions used herein have the ordinarytechnical meaning as is accorded to such terms and expressions bypersons skilled in the technical field as set forth above except wheredifferent specific meanings have otherwise been set forth herein.

DETAILED DESCRIPTION

In one aspect of the present disclosure, a GNSS-enabled device isdisclosed that provides improved location accuracy while utilizing alimited power source. The GNSS-enabled device includes GNSS circuitryconfigured to utilize electrical power from the limited power source ofthe device and receive location data from one or more satellite systemsorbiting the earth. The satellite systems may include, for example, theGalileo, Beidou, GLONASS, or GPS satellite constellations.

The GNSS-enabled device includes a controller operatively coupled to thelimited power source, which may be but is not limited to anon-rechargeable battery, and the GNSS circuitry. The controller isconfigured to, among other operations, manage the on-time of the GNSScircuitry and preserve the stored energy of the limited power source.The controller may include, for example, a general-purpose processor, ora specifically designed application specific integrated circuit (ASIC).The controller may be operatively coupled to one or more sensors, whichmay be integral with the GNSS-enabled device or operably coupled theretovia wired or wireless approaches. The one or more sensors may beconfigured for sensing one or more parameters of a mobile railway assetsuch as but not limited to a mobile railway asset. The controller mayalso be operatively coupled to communication circuitry for communicatingdata via one or more long-range wireless protocols and/or via one ormore short-range wireless communication protocols. The communicationcircuitry and the one or more sensors may be wholly contained in theGNSS-enabled device. In another embodiment, the one or more sensors mayinterface with the device via one or more ports or wirelesscommunication protocols.

The controller has different modes that achieve different objectives forthe GNSS-enabled device. The controller has a power saving mode whereinthe controller inhibits the GNSS circuitry from receiving location datafrom satellites. The controller also has a standard accuracy modewherein the controller permits the GNSS circuitry to receive locationdata for a first time period. The controller may reconfigure from thepower saving mode to the standard accuracy mode according to one or morecriteria. For example, the controller may reconfigure from the powersaving mode to the standard accuracy mode according to a fixed orvariable schedule. As another example, the controller may apply a firstheuristic to the GNSS data and/or data from one or more sensors todetermine if a change in a mobile railway asset parameter has occurredand reconfigure the controller from the power saving mode to thestandard accuracy mode.

Further, the controller has a higher accuracy mode wherein thecontroller permits the GNSS circuitry to receive location data for asecond time period longer than the first time period. The controller mayreconfigure from the standard accuracy mode to the higher accuracy mode,or from the power saving mode to the higher accuracy mode, in responseto a determination of a mobile railway asset event. For example, thecontroller may apply a second heuristic to the GNSS data and/or datafrom one or more sensors to determine if a change in a mobile railwayasset parameter has occurred and reconfigure the controller from thepower saving mode or standard accuracy mode to the higher accuracy mode.

The controller may have a default power mode, such as the power savingmode which the controller reverts to after a higher-energy consumptionpower mode such as the standard accuracy mode or the higher accuracymode. In the power saving mode, the controller may inhibit the GNSScircuitry from receiving location data by, for example, turning off theGNSS circuitry or by disabling the reception of GNSS data. Thispreserves the life of the power source by minimizing energy usage of theGNSS circuitry. As an example, the power saving mode may involve thecontroller placing the GNSS circuitry in a trickle or hibernate modewherein the controller provides the minimum amount of electrical energyto the GNSS circuitry required to maintain previously-received ephemerisdata that is stored in a memory of the GNSS circuitry. The trickle orhibernate mode may involve the controller providing a de minimis amountof energy, such as 5 mA, to the GNSS circuitry. Providing a de minimisamount of energy to maintain the ephemeris data in the memory of theGNSS circuitry in the hibernate mode of the controller avoids the GNSScircuitry going through a startup sequence that may be undesirably longand consume an undesirable amount of electrical energy for certainsituations. In the startup sequence, the GNSS may have to receive GNSSdata for a time period sufficient to gather enough GNSS data, includingcurrent ephemeris data, to calculate a location fix of the GNSScircuitry. By providing the de minimis amount of energy to the GNSScircuitry, the ephemeris data is kept in the memory of the GNSScircuitry and the startup sequence is avoided. The ephemeris data forthe GNSS satellites changes relatively slowly, such as over severalhours, which permits the ephemeris data stored in the memory of the GNSScircuitry operating in hibernate mode to be sufficiently accurate toutilize in location calculations. However, in some embodiments the powersaving mode may involve turning off power to the GNSS circuitry wherethe startup sequence consumes an acceptable amount of electrical energy.

In one embodiment, the controller reconfiguring from the power savingmode to the standard accuracy mode may include the controller sending acontrol signal to the GNSS circuitry that toggles the GNSS circuitryfrom hibernate to a powered state wherein a receiver of the GNSScircuitry receives GNSS data from GNSS satellites. Conversely, thecontroller reconfiguring from the standard accuracy mode to the powersaving mode may include the controller sending a control signal to theGNSS circuitry that causes the GNSS circuitry to hibernate andde-energize the receiver of the GNSS circuitry.

In the standard accuracy mode, the controller permits the GNSS circuitryto receive GNSS data for a first time period. The controller may provideelectrical power to the GNSS circuitry greater than the de minimisamount provided in the power saving mode, such as 25 mA. The first timeperiod may be fixed or variable. The variable period of time may be theperiod of time required for the controller and/or GNSS circuitry toachieve a threshold location accuracy for the GNSS-enabled device. Forexample, the first time period may be the time required to receive GNSSdata including timing data from a minimum of four satellites with validephemeris data. The time it takes to acquire data from these satellitesmay vary, but the expectation is typically this will occur between, forexample, five and forty seconds depending on the length of time betweenthe previous acquisition and the environment. As another example, thefirst time period may be the time required to receive enough GNSS datato calculate a predetermined number of valid location fixes. The GNSScircuitry may calculate a location fix every second that the GNSScircuitry is operating in standard accuracy mode.

The controller may utilize the standard accuracy mode to obtain GNSSdata when the accuracy of the location of the mobile railway asset isnot as critical, such as when the mobile railway asset is in transit.The controller may also utilize the standard accuracy mode for updatesof the location of the mobile railway asset according to a predeterminedschedule. The controller may have a timer to monitor the length of thefirst time period and return to the power saving mode if the thresholdlocation accuracy is not achieved, such as forty-five seconds, sixtyseconds, or ninety seconds. The threshold location accuracy may not beachieved, for example, if the GNSS satellite signals are blocked byterrain or a mobile railway asset on an adjacent track.

In the higher accuracy mode, the controller permits the GNSS circuitryto receive GNSS data for a second time period that is longer than thefirst time period of the standard accuracy mode. By permitting GNSScircuitry to receive newly updated GNSS data, which will be moreprecise, and acquiring data for a longer time period, more GNSS data canbe received and potentially from a greater number of visible satellitesin a GNSS. The more precise GNSS data, which includes ephemeris data andtiming data, from many visible GNSS satellites provides more informationfor use in calculating the location of the mobile railway asset which,in turn, permits a more accurate calculation of the location.

The controller may also filter the GNSS data received during the secondtime period. For example, if the second time period is forty seconds thecontroller may discard the location fixes of the first thirty secondsand keep the location fixes for the last ten seconds. The controller maythen average the location fixes of the last eight to ten seconds todetermine the location of the GNSS-enabled device.

The controller may utilize the higher accuracy mode according to apredetermined or random schedule to supplement location estimates madeusing GNSS data from the standard accuracy mode. Alternatively or inaddition, the controller may utilize the higher accuracy mode inresponse to a determination of a mobile railway asset event such as themobile railway asset entering a geofenced rail yard or receiving datafrom a sensor mounted, for example, on the hatch of a railcar.

The second time period may be fixed or variable. A fixed second timeperiod may be, for example, in the range of 35 seconds to 60 secondssuch as 40 seconds. A variable second period of time may be the periodof time required for the controller and/or GNSS circuitry to achieve athreshold location accuracy for the GNSS-enabled device. The thresholdmay be higher than the threshold utilized for the first period of time,such as the GNSS receiver receiving GNSS data from six satellites in thesecond time period rather than four satellites in the first time period.The controller may have a timer to monitor the length of the second timeperiod and return to the power saving mode if the threshold locationaccuracy of the higher accuracy mode is not achieved, such as twominutes.

With reference to FIG. 5 , the GNSS data received during the first timeperiod of the standard accuracy mode may provide a range of calculatedlocations of the mobile railway asset 202 within the radius R¹. Thecalculated locations may be on track 1, track 2, or track 3 of a railyard, and the calculated locations may actually be on the railcars 201,203, 204, 205. This level of accuracy may be acceptable if it issufficient to know that the railcar is in the rail yard. However, thislevel of accuracy may not be acceptable for determining which track themobile railway asset 202 is on, such as when assembling a train consistaccording to a train manifest. By contrast, the GNSS data receivedduring the second time period of the higher accuracy mode may beanalyzed to provide a range of calculated locations of the railcar 202within radius R². The tighter range of locations of the railcar 202permits the railcar 202 to be identified as being on track 1 of the railyard.

In one embodiment, the data collected in the second time periodassociated with the higher accuracy mode may be post-processed bysorting each reading received during the second time period based on ameasure of accuracy to form sorted location data of varying accuracy(accuracy may be based on metrics such as horizontal dilution ofprecision (HDOP) and/or satellite count); discarding a portion of thesorted location data to form a final array of readings; and calculatingthe location of the mobile railway asset based on the final array ofdata. It has been discovered that by utilizing the longer, second timeperiod (where location data will be the most up-to-date) and thenperforming post processing on the received location data, the accuracyof the calculation will likely be increased with marginal increase inenergy consumption compared to the standard accuracy mode.

Further, the same process described above can be repeated, over severalinstances, separated by a period of time (e.g., 60 minutes) to collect asecond array of location data, that can be sorted and filtered in thesame manner. Through this process, multiple instances of location datacollection can be averaged together in aggregate, to permit a moreprecise determination of a mobile railway asset location.

Because the power cost is higher in the higher accuracy mode, the use ofthe higher accuracy mode may be controlled based on the occurrence of amobile railway asset event. For example, the railcar may be equippedwith one or more sensors to determine when, for example, the railcar ismoving or being loaded. The controller may then choose between operatingin the power saving mode, the standard accuracy mode, and the higheraccuracy mode based on one or more parameters to determine which mode tooperate in and to only enter the higher accuracy mode when a moreaccurate location is thought to be desired based on the one or moreparameters.

The GNSS-enabled device also includes communication circuitry capable ofshort range and/or long-range wireless communication. In the context ofa train consist, a short range communication is generally considered tobe a communication between components on the train consist, such as acommunication between a wireless sensor node and a communicationsmanagement unit, and a long range communication is a communication witha device off of the train such as a cellular tower.

Long-range wireless communication with a network, such as a cellularnetwork and/or satellite, via the communication circuitry is a highlypower intensive operation much like receiving GNSS data that rapidlyconsumes stored energy of the power source. As such, the GNSS-enableddevice may not maintain a downlink/uplink with the network unless thecontroller determines that such a link is necessary to communicatelocation data or other data. A similar energy consumption problem existswith short-range communications via the communication circuitry, albeitto a lesser extent. The short-range communication may include, forexample, communication with other devices of a network of the train viaa IEEE 802.15.4 protocol. In one embodiment, the GNSS-enabled devicedecides when to establish long-range and/or short-range communicationswhen such communications are required rather than receiving instructionsfrom a remote computer to initiate communications.

In one embodiment, the controller may enter the higher accuracy mode aplurality of times in response to a mobile railway asset event,determination of the mobile railway asset being stationary, and averagethe calculated mobile railway asset locations to obtain a highlyaccurate location determination for the stationary mobile railway asset.For example, the one or more sensors of the GNSS-enabled device mayinclude a motion sensor. Upon the motion sensor detecting the mobilerailway asset is stationary, the controller starts a timer (e.g., thirtyminutes) and enters the higher accuracy mode if the timer expireswithout the mobile railway asset being moved. The controller maydetermine the location of the mobile railway asset using the locationinformation gathered by the GNSS circuitry during the higher accuracymode. The controller repeats the higher accuracy mode and locationdetermination after set periods of time, e.g., 45 minutes. The locationsof the mobile railway asset determined by the controller are thenaveraged to provide a more accurate result.

With reference to FIGS. 1A, a train consist 2 is provided that includesa connected group of one or more locomotives 4 and one or more railcars100. The train consist 2 includes one or more railway asset nodes(“RANs”) of the rail cars 6. In some embodiments, the RANs includecommunications management units (“CMU”) 12 located on railcars 6 thatcontrol a respective railcar-based network 14. The RANs mayalternatively or additionally include one or more sensor nodes (“SNs”)and/or one or more wireless sensor nodes (“WSNs”) 16. The one or moreRANs may communicate with other RANs of the train consist 2 and/oranother train consist 2. Alternatively or additionally, the RANs maycommunicate with one or more networks instantiated off of the trainconsist 2. For example, a RAN may communicate with a long-range wirelesscommunication network such as a cellular network. As an example in thisregard, the RAN may communicate with a remote computer via a long-rangewireless communication network and the internet.

In one embodiment, the CMU 12 supports one or more WSNs 16 in therailcar-based network 14. The CMU 12 and WSNs 16 may communicate usingwired or wireless approaches, such as a one or more open standardprotocols such as the IEEE 802.15.4 radio standard.

The train consist 2 includes a train-based network 20 that includes theRANs, such as the CMUs 12, of the railcars 100. The RANs of thetrain-based network 20 may also include a powered wireless gateway(“PWG”) 22 that may be located on the locomotive 4. The CMUs 12 and thePWG 22 may communicate using one or more wired or wireless approaches.The CMUs 12 and the PWG 22 include similar components except that theCMU 12 is self-powered whereas the CMU 12 utilizes power from anexternal source, such as the locomotive 4.

With reference to FIGS. 1B and 2 , one or more of the railcars 100includes a GNSS-enabled device 200. The GNSS-enabled device 200 mayconstitute one of the RANs discussed above. In some embodiments, theGNSS-enabled device 200 may be the CMU 12 or the WSN 16 discussed above.In the example of FIGS. 1B and 2 , a railcar system 10 is provided thatincludes railcar 100 having a CMU 12 in the form of the GNSS-enableddevice 200 and one or more WSNs 16 such as sensors 110, 120, 130.

In some embodiments, the CMU 12 communicates its most accurate locationcalculation for the respective railcar 100 to the PWG 22 for a giventime period and the PWG 22 communicates the location to an externaldevice such as a remote server 22B via a network 22A such as a satellitenetwork, cellular network, and/or the internet. The PWG 22 and/or theremote server 22B may aggregate over time the location of the railcar100 calculated by the CMU 12. If the railcar 100 remains stationary, thelocations over time are continually averaged which gives a more accuratelocation for the railcar 100. The remote server 22B may be maintained ata remote railroad operations center as one example.

Regarding FIGS. 1B and 2 , the GNSS-enabled device 200 includes ahousing 210 configured to be mounted to the railcar 100. The housing 210may have a bracket for connecting the housing 210 to the railcar 100.The bracket can be magnetic or non-magnetic. In another embodiment, thehousing 210 may have flanges with openings that receive fasteners forconnecting the housing 210 to the railcar 100. Alternatively oradditionally, the housing 210 may be welded to the railcar 100. Thehousing 210 contains a controller 250, which includes a processor 251and a memory 253, as well as GNSS circuitry 280. When the controller 250indicates for the GNSS circuitry to be energized, in either standard orhigher accuracy mode, the GNSS circuitry 280 receives location data fromvisible GNSS satellites. The housing 210 also contains communicationcircuitry 260 for communicating data indicative of the location of therailcar 100 to one or more external devices 230, such as a remote servercomputer, desktop computer, tablet computer, and/or a smartphone. Thecommunication circuitry 260 may communicate the data using radiofrequency signals. In one embodiment, the communication circuitry 260may communicate with the external device 230, for example, via acellular network, a satellite network, another wireless network, and/orthe internet. The communication circuitry 260 may also utilize shortrange wireless communication protocols for communicating with nearbydevices, such as one or more sensors 110, 120, 130 of the railcar 100and GNSS-enabled devices 200 of nearby railcars. The short rangewireless communication protocols may include, for example, Wi-Fi, NFC,and Bluetooth as examples.

In some embodiments, the processor 251 or the external device 230determines a location of the railcar 100 based on the location datareceived by the GNSS circuitry 280. As discussed in greater detailbelow, the controller 250 has a power saving mode wherein the controller250 inhibits the GNSS circuitry 280 from receiving location data, astandard accuracy mode wherein the controller 250 permits the GNSScircuitry 280 to receive location data for a first time period, and ahigher accuracy mode wherein the controller 250 permits the GNSScircuitry 280 to receive location data for a second time period longerthan the first time period.

The railcar system 10 includes a GNSS-enabled device 200 and the one ormore sensors 110, 120, and 130 as shown in FIG. 1 . The sensors 110,120, and 130 are configured to determine one or more parameters of therailcar 100. The sensors 110, 120, and 130 may be, for example, one ormore of: an accelerometer, a magnetometer, an image sensor, a wheelencoder, a weight sensor, a gyroscope, a link sensor, a hatch statesensor, a handbrake position sensor, a strain gauge, a reed switches, apressure transducer, a temperature sensor, a displacement sensor, aspeed sensor, and combinations thereof. The railcar 100 may be equippedwith any number of sensors. The controller 250 may be configured toenter the higher accuracy mode in response to a mobile railway assetevent such as a change in a parameter of the railcar, e.g., the railcar100 stopping.

One or more of the sensors 110, 120, and 130 may connect to thecommunication circuitry 260 of the GNSS-enabled device 200 via one ormore short-range wireless protocols. In another embodiment, one or moreof the sensors 110, 120, and 130 may connect to ports 212, 213, 214 ofthe GNSS-enabled device 200 or via, for example, a CAN or LIN bus. TheGNSS-enabled device 200 may include one or more internal sensors 205contained within the housing 210 of the device 200. For example, thehousing 210 may contain an accelerometer, a magnetometer, and/or animage sensor.

With reference to FIG. 2 , the GNSS-enabled device 200 includes alimited power source 270. Such limited power source, for example, couldbe a battery, super capacitor and/or an energy harvesting system such assolar, vibration, or temperature differences. In one embodiment, thelimited power source 270 includes at least one battery 273, such as alithium ion or nickel-metal hydride battery, and one or morebattery-level or charge monitoring circuits 277. The battery 273 may beconfigured to power the controller 250, the communication circuitry 260,the GNSS circuitry 280, and the one or more internal sensors 205. Thecontroller 250 operates the communication circuitry 260, the GNSScircuitry 280, and the one or more internal sensors 205 while minimizingthe energy consumption of these components. The battery 273 mayadditionally power peripheral devices, such as sensors, connected to theports 212, 213, 214.

Power received at any one of the one or more ports 212, 213, 214 may beused to power the GNSS-enabled device 200, to charge the battery 273 ofthe GNSS-enabled device 200, or both. For example, the GNSS-enableddevice 200 may include or be operatively coupled to a solar panel thatprovides electricity to the port 212 and the charge monitoring circuit277 charges the battery 273 using the solar power. As another example,the GNSS-enabled device 200 may include or be operatively coupled toother energy harvesting devices such as devices that harvest energy fromvibration, rotational forces, or from differences in temperature as someexamples.

The communication circuitry 260 of the GNSS-enabled device 200 may beconfigured to communicate with external devices 230, such as sensors orother GNSS-enabled devices 200, using one or more short-rangecommunication protocols such as, for example, Bluetooth® or Bluetooth®low-energy. The communication circuitry 260 may be configured tocommunicate with one or more external devices 230 using one or more longrange protocols such as WiMax, LoRaWAN, and/or cellular networks (3G,4G, 4G LTE, 5G). Further, the communication circuitry 260 may beconfigured to communicate over the internet. The GNSS circuitry 280 mayinclude any commercially available GNSS chip or chip set that isconfigured to receive location data from one or more satelliteconstellations such as the Galileo, Beidou, GLONASS, or GPS satelliteconstellations. For example, the GNSS circuitry 280 may include aSiRFstar IV navigation processor by Qualcomm.

The controller 250 has at least three different modes that correspond todifferent levels of energy consumption and GNSS-enabled device 200location accuracy. The at least three modes of the controller 250include a power saving mode, a standard accuracy mode, and a higheraccuracy mode. Although these modes are described, it will beappreciated that more modes may be utilized as desired to providedifferent durations of operation of the GNSS circuitry 280 and differentlevels of GNSS-enabled device 200 location accuracy.

The controller 250 may be programmed to change the power mode of theGNSS-enabled device 200 in response to a mobile railway asset event suchas changes in parameters of the railcar 100 detected by the one or moresensors 110, 120, 130, and 205, upon expiration of one or more timers,according to a predetermined schedule, or combinations thereof.

With reference to FIG. 3 , an example method 300 is provided ofoperating the GNSS-enabled device 200. The controller 250 of theGNSS-enabled device 200 starts in the power saving mode 302. The powersaving mode 302 may be initiated when the controller 250 puts itself tosleep. In one embodiment, the controller 250 in the power saving mode302 is powered down or dormant and does not draw any energy from thebattery 273. The controller 250 wakes up in response to a signal at aninput of the controller 250, such as a signal from one or more of thesensors 110, 120, 130, 205. As an example, the controller 250 mayinclude a microprocessor that wakes up in response to a voltage appliedto one or more of the pins of the microprocessor.

When the controller 250 of the GNSS-enabled device 200 wakes up, thecontroller analyzes the signal at the input of the controller 250 todetermine 304 whether there is a mobile railway asset event, such as achange in at least one parameter of the railcar 100. The mobile railwayasset event may be, for example, an alert, a measurement, a parametermeeting a threshold, a parameter being inside or outside of a range,and/or a change in a parameter. The controller 250 uses data collectedfrom the sensors 110, 120, 130, and/or 205 and/or the GNSS circuitry 280and may apply heuristics to draw conclusions based on the analysis. Thechart below provides examples of parameters sensed, sensor(s) utilized,and descriptions of the heuristics applied to analyze the data.

Parameter Sensed Input Device Output Heuristic Bearing TemperatureBearing Bearing fitting temperature is Fitting Sensor Temperaturecorrelated to bearing cup Temper- temperature using empirical aturedata. Hatch Reed Switch Hatch open/ Determine open/closed state Positionclose dependent upon state of switch. Pressure Pressure Brake Thepressure transducer is Transducer pressure fitted directly to thetrainline for measuring pressure. Hand brake Strain Gauge Hand brakeHand brake link strain is Link On/Off correlated to the ON/OFF Strainstatus of the hand brake. Bolster Hall Effect Car Load Bolster/sideframe Displace- Sensor displacement is measured and ment springstiffness data is used to convert displacement to load. Bolster ReedSwitch Car Empty/ The relative position of position Full bolster/sideframe is measured. The LOADED position is determined using empiricaldata or spring stiffness. Inner External Tank Car Inner jacket surfaceJacket Temperature Commodity temperature on a tank car is Temper- SensorTemperature determined and commodity ature temperature can be estimatedusing theoretical conduction/convention laws. Bolster Limit Switch CarEmpty/ A limit switch is mounted to Position Full the side frame andactivated when the bolster/side frame position is in the loaded state.Sill Accelero- Coupler Impact data is collected. Accelero- meter ForceUsing empirical data, a meter modal influence matrix can be computed fordifferent coupler types that relates the impact data to the output.Using an FFT on the sampled data, and multiplying by the inverse of themodal matrix yields the input in the frequency domain. This input can beconverted to the time domain to yield the coupler force. BearingAccelero- Bearing An fitting mounted Fitting meter Fault accelerometercan be used to Accelero- Indicator sample dynamic bearing data. meter AnFFT can be used on data sets and plotted over time to isolate dominantmodes and any shifting or relative amplification. Amplification atrolling frequency indicates a likely fault. Radial Axle Accelero-Vehicle An axle mounted Accelero- meter Speed accelerometer can be usedto meter measure radial acceleration. The radial acceleration can beconverted to vehicle speed using simple dynamics using the wheel andaxle diameters. Bearing Accelero- Bearing A fitting mounted Fittingmeter Fault accelerometer can be used to Accelero- sample dynamicbearing data. meter Kurtosis can be computed as an indicator of bearingdamage. Kurtosis is measured in the time domain and requires computationof a probability density function. Bearing Piezo-electric BearingSampled acoustic data can be Fitting sensor, Fault used for either anacoustic Acoustics microphone, noise response or Acoustic and Emissionwhich is ring-down accelerometer counts and amplitude. Empirical datafrom defective bearings is needed. Temper- Temperature Commodity/ Atemperature sensor can be ature sensor Fluid used to measure surfacePressure temperature of a pressure vessel (Tubing, tank, etc.). Heatconduction equations can be used to convert the surface temperature tofluid temperature. Using published data for the working fluid, thetemperature can be converted to pressure. Displace- Displacement CouplerCoupler displacement is ment Sensor Force measured and correlated toforce using force-closure curves. Axle RPM Inductive Vehicle Aninductive proximity Type Speed sensor facing the axle can Sensorgenerate a signal in response to an exciter ring on the axle, andconverted to vehicle speed using wheel and axle diameters. BearingAccelero- Track Sensor is mounted on an Fitting meter Damage fitting orother truck Accelero- Detection component to sample meter dynamic data.A Probability Density Function and Kurtosis can be computed from thedata. High Kurtosis, or impulsivity, will indicate track defects. Atransfer function relating the wheel input to the fitting is needed, andcan be determined empirically or by creating a theoretical model.Bearing Accelero- Truck Sensor can be mounted on an Fitting meterHunting fitting or other truck Accelero- Detection component to samplemeter dynamic data. A simple algorithm could use an FFT to isolate knownhunting frequencies. More sophisticated algorithms could detect flangeimpacts using time-series data. Wheel Infra-Red Wheel Tread Wheeltemperature is Temper- Temperature Temp correlated to tread ature Sensortemperature using empirical data. Proximity Ultrasonic Empty/Full Anultrasonic sensor could be Sensor status used to detect the presence oflading in tank-cars, box-cars, covered hoppers, etc. Strain Load CellCar Load Load cell on multiple places of the truck. Displace- ReedSwitch Hand brake Position of a hand brake ment On/Off chain isdetermined and correlated to On/Off Status. Bolster Accelero- Truck tiltUsing a 3-axis accelerometer Accelero- meter angles fixed to a bolster,the meter gravitational field can be used to measure the respectiveroll, pitch, and yaw angles with respect to fixed-earth coordinates.Hatch Accelero- Hatch Tilt Accelerometer measures the Accelero- meterrelative tilt of hatch with meter fixed-earth coordinates. Geofence GNSSLocation Location of mobile railway circuitry asset is checked todetermine whether mobile railway asset entered geofenced area. SpeedGNSS Speed Mobile railway asset stops. circuitry

Other examples of a mobile railway asset event include, for example, theexternal device 230 such as a remote server computer requesting thatthat GNSS-enabled device 200 provide the location of the railcar 100. Asan example, a customer may want to know the exact location of therailcar 100 and the railroad company's server computer sends a requestto the GNSS-enabled device 200 to provide a high-accuracy calculation ofthe location of the railcar 100. As another example, a mobile railwayasset event may include a railyard device, such as a stationary gateway706 shown in FIG. 7 , requesting that the GNSS-enabled device 200provide a high-accuracy calculation of the location of the railcar 100.

Regarding FIG. 3 , if there is no mobile railway asset event, thecontroller 250 determines 306 whether a timer has expired. If the timerhas not expired at operation 306, the controller 250 puts itself back tosleep. The timer sets a fixed or variable time period the controller 250waits between operations of the GNSS circuitry 280.

If the controller 250 determines 306 that the timer has expired, thecontroller 250 enters the standard accuracy mode 308 and energizes theGNSS circuitry 280 for a first time period. The first time period may bein the range of, for example, approximately four to approximately 40seconds, such as 10 seconds. Once energized, the GNSS circuitry 280starts receiving GNSS data including ephemeris data and timing data fromsatellites of the GNSS. The GNSS data is timestamped as it is receivedto permit the controller 250 to be able to determine location as well aspermit the controller 250 to identify when a GNSS data set (includingephemeris and timing data) was received during the first time period.The GNSS circuitry 280 may automatically discard or not use the initialGNSS data sets, such as GNSS data sets received during a first eightseconds of a first time period lasting ten seconds, to filter thereceived GNSS data.

The controller 250 stops powering or energizing the GNSS circuitry 280at the end of the first time period so that the GNSS circuitry 280 stopsreceiving GNSS data. As noted above, the first time period may be fixedor variable. For example, the controller 250 energizes the GNSScircuitry 280 until the GNSS circuitry 280 receives three validreadings. Whether a reading is valid or not may be determined based ondetails from the GNSS circuitry 280, and/or configured thresholds likeHDOP, satellite count, and elevation mask. The time period required toobtain the three valid readings may vary depending on, for example, thesatellites visible to the GNSS circuitry 280, impairment conditions suchas atmospheric attenuation when experiencing precipitation, destructiveinterference from high signal reflection and spectral congestionenvironments, electromagnetic interference from locomotives engineemissions or traversing through electrified track environment,interference aberrations from high or sudden vibration conditions due toengine startup, rough track, wheel defects, subsidence and/or thesurrounding terrain.

In one embodiment, the first time period ends once the configured numberof valid readings have been obtained during the configurable searchtime. The controller 250 then stops energizing the GNSS circuitry 280and the GNSS circuitry 280 returns to the power saving mode 302.

In one embodiment, the controller 250 calculates the location of themobile railway asset 100 based on the received location data from thefirst time period. As an example the controller 250 may discard one ormore of the initial readings to help improve accuracy withoutsignificant power cost, because the first few readings may have beencalculated based on only a few visible satellites, for example, foursatellites, whereas subsequent readings may have been based on a greaternumber of visible satellites, for example five or six satellites,available as their individual satellite ephemeris and timing data iscaptured. Further, the GNSS circuitry 280 itself may includeoptimization routines that may be used as more data is collected.

Regarding FIGS. 10A and 10B, the satellites 1010 of a GNSS constellationmove in the direction of the Earth's rotation so that the satellites1010 visible to the GNSS circuitry 280 of a GNSS-enabled device 200change over time. Regarding FIG. 10A, during the first time period foursatellites 1010 are visible to the GNSS circuitry 280. Regarding FIG.10B, during the second time period six satellites 1010 are visible tothe GNSS circuitry 280.

The controller 250 may energize the communication circuitry 260 at thesame time as the GNSS circuitry 280 or the communication circuitry 260may be powered-up at a different time such as after the collection oflocation data by the GNSS circuitry 280. After the controller 250determines the location of the mobile railway asset 100 from thereceived location data of the first time period, the controller 250optionally causes the communication circuitry 260 to communicate 311 thedetermined location of mobile railway asset 100 to the external device230, such as by transmitting data indicative of the location of themobile railway asset 100 to a remote server via, for example, the PWG22, a cellular network, and the internet. The controller 250 powers downthe communication circuitry 260 once the transmission of the locationdata to the external device 230 has completed.

In another embodiment, the controller 250 does not calculate the finallocation of the mobile railway asset 100. Rather, the controller 250communicates 311 one or more samples of the received GNSS data by thecommunication circuitry 260 to the external device 230. For example, thesamples of the received GNSS data include a first set of samples and asecond set of samples. The controller 250 causes the communicationcircuitry 260 to only transmit the second set of the samples. As anotherexample, the controller 250 may discard the first two readings oflocation data and cause the communication circuitry 260 to onlycommunicate a third reading to the external device 230. Alternatively oradditionally, the external device 230 may then use multiple instances oflocation data from the controller 250 as well as other external sourcesto calculate an accurate location of the railcar 100.

The controller 250 monitors data from the sensors 110, 120, 130, 205 andthe GNSS circuitry 280 and determines 310 whether there is a mobilerailway asset event for the railcar 100. The mobile railway asset eventmay be, for example, a change in acceleration of a component of therailcar, a change in a sound produced by a component of the railcar, achange in position of a hatch or door of the railcar, or the railcarentering a geographic area such as a geofenced rail yard. If there is nomobile railway asset event of the railcar 100, the controller 250determines 314 whether a secondary timer has expired. The secondarytimer is longer than the timer checked at operation 306 and may be usedto periodically cause the controller 250 to enter the higher accuracymode 314. The periodic collection of location data in the higheraccuracy mode 314 may be desirable to provide improved accuracy duringtravel of the railcar 100 even though there is no mobile railway assetevent of the railcar 100.

The controller 250 enters the higher accuracy mode 314 upon there beinga mobile railway asset event at operations 304 or 310 or, optionally,the second timer expiring at operation 312. The higher accuracy mode 314involves the controller 250 energizing the GNSS circuitry 280 for asecond time period longer than the first time period. The second timeperiod may be, for example, in the range of 30 seconds to 50 secondssuch as 40 seconds. The second time period may be fixed or variable,such as lasting until a predetermined number of location data readingshaving an accuracy above a predetermined threshold have been obtained.

The longer second time period permits the GNSS circuitry 280 to receivemore GNSS data and calculate a greater number of locations of the mobilerailway asset that may be filtered and/or averaged to calculate thelocation of the railcar 100. More specifically, energizing the GNSScircuitry 280 for at least a specific period of time, for example 30seconds, permits new GNSS data readings to be collected from asufficient number of satellites to make accurate predictions regardingthe location of the railcar 100. For example, receiving GNSS data fromfour to six satellites may take approximately 30 seconds.

Because the GNSS circuitry 280 will be powered for a specific period oftime, for example, at least 30 seconds, it will be able to receive themost up-to-date ephemeris data containing positional details of thevisible satellites. This is relevant because a faster, but lessaccurate, location could potentially be calculated based on a smallernumber of satellites that already have ephemeris data stored in the GNSScircuitry 280. But the available satellites may be limited to, forexample, four satellites and the satellites may be at a differentposition than is stored in the GNSS circuitry 280, which can result in aless accurate reading. In other words, the GNSS circuitry 280 may make alocation determination based on stale ephemeris data if the GNSScircuitry is energized only for a period of time to obtain GNSS datafrom four satellites. Keeping the GNSS circuitry 280 energized for aspecific period of time, for example at least 30 seconds, allows forephemeris data to be received from all visible satellites in theconstellation.

The controller 250 powers down the GNSS circuitry 280 at the end of thesecond time period and the controller 250 returns to the power savingmode. The controller 250 may determine the location of the railcar 100based on the GNSS data received during the second time period and causethe communication circuitry 260 to communicate 316 the location to theexternal device 230. Alternatively, the controller 250 may facilitatecommunication of at least a portion of the received GNSS data to theexternal device 230 and the external device 230 calculates the moreaccurate location of the railcar 100. It will be appreciated that theoperation of the communication circuitry 260 to communicate data to theexternal device 230 may be concurrent with, partially concurrent with,or subsequent to the first and second time periods. Further, thecontroller 250 may store the GNSS data and/or the averaged GNSS data inthe memory 253. The controller 250 may store the data until a thresholdnumber of measurements has been accumulated and then operate thecommunication circuitry 260 to communicate the stored data to theexternal device 230.

The controller 250, or the external device 230, that determines thelocation of the railcar 100, may utilize a post-processing algorithmthat operates as a filter to obtain a high-accuracy location of therailcar 100 from the GNSS data received during the second time period.In one embodiment, the GNSS data collected during the second time periodis time stamped as the GNSS data sets are received. The post-processingalgorithm is performed by a method that involves discarding or not usinga first portion of the GNSS data collected, such as the first eight setsof GNSS data, as the earlier GNSS data sets may contain fewer satellitesas part of the calculation, and/or ephemeris data that is out of date.As an example, the second time period may be 40 seconds and the methodincludes discarding or not using ephemeris data collected during a firstportion of the second time period, such as during the first 30 secondsof the 40 second time period. The remaining second portion of the GNSSdata, such as data collected during the last 10 seconds, is used todetermine the location of the railcar 100. The second portion of theGNSS data may be more accurate than the first portion (as describedabove) such that determining the location based on only the secondportion provides satisfactory accuracy.

The controller 250 may use a predetermined or learned duration of thefirst time period and/or the second time period as the basis fordiscarding data. The controller 250 may learn the appropriate timeperiod for discarding GNSS data through feedback calculations performedby the controller 250 or the external device 230 that specifies whetheror not the calculated location of the railcar 100 was within anacceptable tolerance. In one embodiment, the time period may be learnedthrough empirical devices in the field. Based on the empirical results,a set of logical rules may be established to provide the time periodthat should be used based on one or more inputs, e.g., time of day, typeof mobile railway asset, and weather. In another embodiment, the timeperiod may be determined using machine learning. For example, real-worldtesting data including environmental inputs, GNSS receiver energizationduration, and resulting location accuracy could be provided to a machinelearning system. The machine learning system would providecategorization for different time periods based on current environmentalinputs and desired accuracy.

With reference to FIG. 4 , another method 400 is provided for obtaininga high-accuracy estimate of the location of the railcar 100 based on theGNSS data received during the second time period. The method 400includes sorting 402 the GNSS data received during the second timeperiod. The sorting 402 may include sorting the GNSS data based onsatellite count, HDOP, and/or other factors. The method 400 includesdiscarding 404 a portion of the GNSS data based on parameters associatedwith each instance of the GNSS data. For example, the GNSS data having asatellite count lower, or HDOP higher (which is less accurate), than aset threshold is discarded. The method 400 further includes calculating406 the location of the railcar 100 based on the remaining readingshaving accuracies above the set threshold.

After the controller 250 enters the higher accuracy mode, the controller250 may send a confirmation request via the communication circuitry 260to request the external device 230, or a user thereof, to specifywhether the controller 250 was correct to enter the higher accuracymode. This feedback allows the GNSS-enabled device 200 to learn when thehigher accuracy mode was properly entered and thus reduces the number ofoccurrences of the device entering the higher accuracy modeunnecessarily.

Regarding FIG. 6 , a system 600 is provided including one or moreGNSS-enabled devices 200 of one or more railcars 601, 602, 603, 604. TheGNSS-enabled devices 200 are capable of communicating with one anothervia a short range communication protocol such as Bluetooth® orBluetooth® low-energy or other wireless communication method. Similarly,each of the GNSS-enabled devices 200 are also capable of communicatingwith one or more external devices 230 using one or more long-rangecommunication protocols such as 3G, 4G, 4G LTE, 5G cellular protocolsand satellite. In one embodiment, the system 600 includes the one ormore external devices 230, such as a local rail yard server 610, a localrail yard database 615, a remote server such as a cloud-based server620, and/or a remote database such as a cloud-based database 625. Thedatabases 615 and 625 may collect and compile learning data from eachpowered GNSS-enabled device 200. As such, when a GNSS-enabled device 200connects to either the server 620 or the server 610, learning dataindicating when a GNSS-enabled device 200 should enter a higher accuracymode may be downloaded to the GNSS-enabled device 200 thus expeditingthe learning process and saving power.

The communication circuitry 260 may connect to the one or more externaldevices 230 using one or more networks. For example and as discussedabove, the GNSS-enabled devices 200 of a train may form a train-basednetwork 20 with a wireless gateway such as a PWG 22 on the locomotive 4of the train 2 (see FIG. 1A). The train-based network 20 may utilize theBluetooth®, Bluetooth® low-energy, and/or 6LoWPAN protocols as someexamples. The PWG 22 may have long-range communication interface (e.g.3G, 4G, 4G LTE, 5G cellular protocol, satellite) that communicates datafrom the GNSS-enabled devices 200 to the one or more external devices230. The PWG 22 may be a powered using the energy from the locomotiveand/or a battery or energy harvesting method. The GNSS-enabled devices200 may be synchronized such that the GNSS-enabled devices 200 form thetrain-based network 20 at scheduled times to facilitate data transferfrom the one or more GNSS-enabled devices 200 installed on railcars 100to the PWG 22, which in turn communicates the data to the one or moreexternal devices 230. This approach conserves battery power by usingshort-range communication protocols of the communication circuitry 260instead of long-range communication protocols. Alternatively, if alocation of two or more railcars 601, 602, 603, 604 is desired, theGNSS-enabled devices 200 of the railcars 601, 602, 603, 604 maycommunicate GNSS data between each other. Then only one of the two ormore GNSS-enabled devices 200 installed on railcars 601, 602, 603, 604need to communicate with the external device 230 using long-rangecommunications thus saving power on the other GNSS-enabled devices. TheGNSS-enabled device 200 may alternatively or additionally communicatewith the external device 230 without the PWG 22, such as by connectingto a cellular or satellite network and/or via a railway connectedfacility gateway such as the stationary gateway 706.

Regarding FIG. 7 , a system 700 is provided for monitoring the locationof a mobile railway asset, such as a railcar 702, in a rail yard. Thesystem 700 includes a GNSS-enabled device, such as a communicationmanagement unit (CMU) 704, and one or more stationary gateways 706. TheCMU 704 may be similar to the GNSS-enabled device 200 discussed aboveand includes communication circuitry configured to communicate with thestationary gateway 706. The CMU 704 may communicate with the stationarygateway 706 using, for example, a wireless protocol such as Wi-Fi,Bluetooth, WiMax, or LoRaWAN. Alternatively or additionally, the CMU 704may also communicate with the stationary gateway 706 indirectly such asvia a powered wireless gateway of a locomotive associated with therailcar 702. The system 700 may also include a remote computer, such asa server computer 708, that communicates with the stationary gateway 706via one or more networks. In one embodiment, the server computer 708communicates with the stationary gateway 706 via the internet and awireless router at the rail yard.

Turning to FIG. 8 , the stationary gateway 706 includes a housing 800that contains GNSS circuitry 802, a processor 804, a memory 806, and acommunication interface 808. The communication interface 808 may includea wireless communication interface for communicating wirelessly via oneor more wireless communication protocols directly or indirectly with theCMU 704. The wireless communication interface may also be configured tocommunicate with the server computer 708. In one embodiment, thecommunication interface 808 includes a wired communication interfacesuch as an ethernet adapter. The stationary gateway 706 further includesa power source 810, which may provide continuous power to permit thestationary gateway 706 to continuously self-survey using GNSS data. Thepower source 810 may include a wired connection to mains electric power.Alternatively or additionally, the power source 810 may include anenergy harvesting power source such as a solar panel system including abattery.

Regarding FIGS. 7 and 8 , when the railcar 702 is within a railwayconnected facility, the system 700 permits an accurate determination ofwhich railroad track 705 the railcar 702 is on. The CMU 704 includes butis not limited to a controller 707, a power source 707A, and GNSScircuitry 709A. The controller 707 has a power saving mode wherein thecontroller 707 inhibits operation of the GNSS circuitry 709 to preservepower of an electrical source of the CMU 704, a standard accuracy modewherein the controller 707 permits the GNSS circuitry 709 to receiveGNSS data for a first time period, and a higher accuracy mode whereinthe controller 707 permits the GNSS circuitry 709 to receive GNSS datafor a second time period longer than the first time period. In oneapproach, the first period of time permits the CMU 704 to determine acurrent location of the railcar 702 and the longer, second period oftime permits the CMU 704 to determine a self-survey location of therailcar 702.

In some instances, the operation of the GNSS circuitry 709 for the firsttime period when the controller 707 is in the standard accuracy modedoes not permit the GNSS circuitry 709 to receive enough GNSS data, orenough accurate GNSS data, from the GNSS satellites to determine whichrailroad track 705 the railcar 702 is on. To achieve the requiredtrack-level accuracy, the controller 707 may enter the higher accuracymode.

Instead of, or in addition to, operating the controller 707 in thehigher accuracy mode, the CMU 704 may accurately determine whichrailroad track 705 the railcar 702 is on by utilizing data from thestationary gateway 706. A railway connected facility, such as a railyard, has one or more stationary gateways 706 adjacent the tracks 705 ofthe facility.

The stationary gateway 706 includes the power source 810 having aconstant power supply, such as a mains electric supply. The power source810 may include a battery backup in the event of disruption to the mainselectric supply and/or an energy harvesting power source such as a solarpanel system. The processor 804 executes GNSS control software stored inthe memory 806 that causes the GNSS circuitry 802 to perform aself-survey over an extended time period, for example 48 hours, whichallows for multiple transitions of the satellite constellation,resulting in a more accurate representation of the stationary gateway.Because the GNSS circuitry 802 can perform a self-survey for an extendedtime period, the stationary gateway 706 may obtain a location of thestationary gateway 706 that is more accurate than the location of therailcar 702 the CMU 704 determines when the controller 707 is in thestandard accuracy mode. The self-survey location determined by thestationary gateway 706 may thereby be a highly accurate benchmarklocation for the stationary gateway 706.

The stationary gateway 706 may be powered all the time and mayconstantly be receiving GNSS data from GNSS satellites. The stationarygateway 706 is stationary and the GNSS data received can be aggressivelyfiltered to keep only the highest quality “fixes” of high satellitecount and low HDOP. All these values can be averaged over many weeks toensure a very accurate self-survey location or benchmark location.

In addition to determining the self-survey location by operating theGNSS circuitry 802 for extended periods, the stationary gateway 706constantly determines current locations of the stationary gateway 706 byoperating the GNSS circuitry 802 for short time periods similar to thefirst time period associated with the standard accuracy mode of thecontroller 707 of the CMU 704. The stationary gateway 706 determinescurrent location error data by comparing the current location of thestationary gateway 706 to the self-survey location of the stationarygateway 706. The difference between the current location and theself-survey location of the stationary gateway 706 at a given timerepresents the error in GNSS data that may be due to the arrangement ofsatellites, weather, terrain, etc. The current location error data mayinclude various types of data indicative of the skew in GNSS data, suchas a current position error vector. As discussed below, the CMU 704and/or the server 708 may use the current location error data inaddition to the GNSS data obtained during the first time period ofoperation of the GNSS circuitry 709 to obtain an accurate determinationof the railroad track 705 the railcar 702 is on without the GNSScircuitry 709 performing a self-survey and requiring electrical powerfor the second time period.

The CMU 704 includes one or more sensors connected to the controller 707so that the controller 707 detects a mobile asset railway event such aswhen the railcar 702 has stopped within the railway connected facility.Upon the railcar 702 being stopped for a predetermined period of time,the controller 707 enters the standard accuracy mode and determines acurrent position based on GNSS data received from the GNSS circuitry709. In one embodiment, the CMU 704 requests the current location errordata from the stationary gateway 706. The difference between the currentlocation and the self-surveyed location may, in one approach, provide acurrent location error. The stationary gateway 706 determines thecurrent location error data, e.g., a current location error vector, bycomparing the current location of the stationary gateway 706 with theself-surveyed location determined by the stationary gateway 706. The CMU704 uses the current location error data to correct the current locationreading obtained by operating the GNSS circuitry 709 for the first timeperiod. For example, the controller 707 of the CMU 704 may add thecurrent position error vector to the current location to obtain a moreaccurate identification of which railroad track 705 the railcar 702 ison.

In another embodiment, the CMU 704 uses the current location error datafrom the stationary gateway 706 to improve the location accuracy of theCMU 704. Because the stationary gateway 706 and the CMU 704 are in closegeographical proximity, such as in the same rail yard, the GNSScircuitries 709A, 802 may see the same GNSS satellites in the samepositions in the sky and may experience similar position errors. Thelocation of the CMU 704 may thereby be calibrated using the error at thestationary gateway 706 to provide a more accurate location without theCMU 704 having to perform a self-survey.

Further, the location of the stationary gateway 706 may be known with ahigh level of confidence based on the extended self-survey(s) performedby the stationary gateway 706 and, in some examples, the stationarynature of the stationary gateway 706. The location of the CMU 704 may beknown with less certainty, due to the shorter GNSS data receivingperiods employed by the CMU 704, in comparison to the self-surveysperformed by the stationary gateway 706, and the movable nature of themobile railway asset. The more certain location of the stationarygateway 706 may be used as a guide when determining the location of theCMU 704. By utilizing GNSS data from the stationary gateway 706, the CMU704 is able to achieve the desired position accuracy while using lesspower than is required for a self-survey.

With reference to FIG. 9 , a method 900 is provided for locating amobile railroad asset at a railway connected facility. The method 900includes operations 902 performed by the stationary gateway andoperations 904 performed by the CMU 704.

At operation 906, the processor 804 of the stationary gateway 706directs a self-survey using GNSS data received by the GNSS circuitry802. The operation 906 may involve receiving GNSS data from the GNSSsatellites during one or more self-surveys. The operation 906 may, forexample, last several days, in some embodiments.

At operation 908, the processor 804 determines a self-surveyed locationof the stationary gateway 706. The self-surveyed location provides ahighly accurate benchmark of the location of the stationary gateway 706.The processor 804 of the stationary gateway 706 stores the self-surveyedlocation in the memory 806 of the stationary gateway 706.

At operations 910 and 912, the stationary gateway 706 receives GNSS datafrom GNSS satellites and determines an instantaneous or current locationof the stationary gateway 706. The GNSS circuitry 802 of the stationarygateway 706 is operated to receive GNSS data from satellites for aperiod of time that is significantly shorter than the period of timeused in operation 906, such as one second or less.

At operation 914, the processor 804 determines current location errordata by comparing the self-surveyed location and the current location.In one embodiment, the processor 804 determines one or more currentposition error vectors that represent the error between the highlyaccurate self-surveyed location and the less accurate current location.

The operations 904 performed by the CMU 704 include operation 916, whichinvolves receiving GNSS data from satellites using the communicationcircuitry 709A of the CMU 704. The operation 916 may involve thecontroller 707 of the CMU being in the standard accuracy mode thereofwhich operates the communication circuitry 709A for the first timeperiod. This relatively short time period permits the GNSS circuitry ofthe CMU 704 to receive enough GNSS data from satellites to obtain arough estimate of the location of the CMU 704 and railcar 702 associatedtherewith. In one embodiment, the first time period of operation 916 issimilar to the length of time the GNSS circuitry 802 is operated atoperation 910.

At operation 918, the CMU 704 receives the current location error datafrom the stationary gateway 706. The CMU 704 may query the stationarygateway 706 for the current location error data. In another approach,the stationary gateway 706 continually wirelessly broadcasts the currentlocation error data for receipt by the CMU 704 when the CMU 704 is inrange of the stationary gateway 706.

At operation 920, the CMU 704 determines a location of the railcar 702using the GNSS data obtained at operation 916 and the current locationerror data received at operation 918. By utilizing the current locationerror data, the CMU 704 may determine the location of the railcar 702without the GNSS circuitry of the CMU 704 having to perform aself-survey.

The CMU 704 may communicate 922 data indicative of the location of therailcar 702 to an external device, such as the server computer 708,locomotive powered wireless gateway or stationary gateway.

In another embodiment, the communication circuitry 709A of the CMU 704communicates data indicative of the current location of the CMU 704 tothe server computer 708. In some embodiments, the communication is viathe stationary gateway 706 and in other embodiments the communicationbypasses the stationary gateway 706 such as the CMU 704 communicatingthe data via the PWG 22. The stationary gateway 706 likewisecommunicates the current location error data to the server computer 708.The server computer 708 determines the location of the railcar 702,including which track 705 the railcar 702 is on, using the current GNSSdata from the CMU 704 and the current location error data from thestationary gateway 706. As an example, the stationary gateway 706 maysend a current position error vector to the server computer 708 everysecond. Further, the server computer 708 may receive current locationerror data from multiple stationary gateways 706 at a facility. Theserver computer 708 may select the current location error data from oneor more of the stationary gateways 706 depending on the current locationprovided by the CMU 704. This permits the server computer 708 to select,for example, the stationary gateway(s) 706 that are closest to therailcar 702 so the error observed by the stationary gateway(s) 706 areeffectively the same as the error observed by the CMU 704.

Regarding FIGS. 9 and 11 , in some situations the satellites 1010visible to the stationary gateway 706 and the GNSS-enabled device 200may be different. The stationary gateway 706 and/or the server computer708 may only provide the current location error data based on thesatellites 1010 that are visible to the GNSS-enabled device 200. Thistailored error data is received by the GNSS-enabled device 200 atoperation 918. Alternatively, the GNSS-enabled device 200 may receive918 current location error data for all the satellites 1010 that arevisible to the stationary gateway 706 and then filter the data to errordata based on the satellites 1010 visible to the GNSS-enabled device200. The stationary gateway 706, sever computer 708, and/or GNSS-enableddevice 200 may set a flag or other indication representing that there isa discrepancy in satellites 1010 visible to the GNSS-enabled device 200.The flag may cause the devices performing the method 900 to tailor theerror data to the satellites visible to the GNSS-enabled device 200.

For example and with reference to FIG. 11 , the railcar 100 ispositioned next to a building 1100 and the GNSS-enabled device 200 ofthe railcar 100. The building 1100 inhibits the GNSS enabled device 200from receiving GNSS data from the satellites 1010A, 1010B, 1010C. Thestationary gateway 706 is mounted on a tall support 1102 and can receiveGNSS data from all of the satellites 1010A-1010G. The GNSS-enableddevice 200 receives 918 the current location error data as determined bythe stationary gateway 706 using only the satellites 1010D, 1010E,1010F, 1010G. The GNSS-enabled device 200 may then determine 920 thelocation of the railcar 100 and communicate 922 data indicative of thelocation of the railcar 100 to an external device.

In some embodiments, the stationary gateway 706 determines 912 thecurrent location of the stationary gateway 706 and communicates thecurrent location to the server computer 708. The server computer 708determines 914 the current location error data and determines 920 thelocation of the railcar 100. Regarding FIG. 11 , The GNSS-enabled device200 calculates location fixes and communicates the location fixes to theserver computer 708 with satellite identifiers indicating the satellites1010D-1010G that sent the GNSS data used by the GNSS-enabled device 200.The server computer 708 commands the stationary gateway 706 to determine912 the current location of the stationary gateway 706 based only onsatellites 1010D-1010G, and to communicate the current location to theserver computer 708. The server computer 708 determines 914 the currentlocation error data based only on satellites 1010D-1010G and determines920 the location of the railcar 100.

Regarding FIG. 12 , a rail connected facility 1200 is provided thatincludes stationary gateways 706 configured to communicate currentlocation error data to railcars such as railcars 1203, 1205, and 1219that include GNSS-enabled devices 1201 similar to the GNSS-enableddevices 200 discussed above. The rail facility 1200 is located within ageofenced area 1202. The railcar 1219 entering the geofenced area 1202along track 1220 causes the GNSS-enabled device 1201 of the railcar 1219to enter a standard accuracy mode and receive GNSS data. TheGNSS-enabled device 1201 of the railcar 1219 may determine a location ofthe railcar 1219 using the received GNSS data and current location errordata received from one or both of the stationary gateways 706. The railfacility 1200 may include one or more dedicated areas such as a loadlocation area 1230, a loaded car staging area 1232, and an empty carstaging area 1234. The areas 1230, 1232, 1234 may be geofenced so thatthe GNSS-enabled devices 200 of the railcars 1203, 1205 determinelocations of the railcars 1203, 1205, using GNSS data and currentlocation error data from the stationary gateways 706, 706 upon therailcars 1201, 1203, 1205, 1218 entering the areas 230, 1232, 1234.

Uses of singular terms such as “a,” “an,” are intended to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms. It is intendedthat the phrase “at least one of” as used herein be interpreted in thedisjunctive sense. For example, the phrase “at least one of A and B” isintended to encompass A, B, or both A and B.

While there have been illustrated and described particular embodimentsof the present invention, it will be appreciated that numerous changesand modifications will occur to those skilled in the art, and it isintended for the present invention to cover all those changes andmodifications which fall within the scope of the appended claims.

What is claimed is:
 1. A method of operating a sensing apparatus for amobile railway asset, the method comprising: at the sensing apparatus:inhibiting, via a controller of the sensing apparatus, global navigationsatellite system (GNSS) circuitry of the sensing apparatus fromreceiving GNSS data from satellites of a GNSS to conserve stored energyof a limited power source of the sensing apparatus; permitting, via thecontroller of the sensing apparatus, the GNSS circuitry to receive GNSSdata for a first time period; wirelessly transmitting data indicative ofa location of the mobile railway asset based at least in part on theGNSS data received during the first time period from communicationcircuitry of the sensing apparatus; in response to a determination of amobile railway asset event, the controller of the sensing apparatuspermitting the GNSS circuitry to receive GNSS data for a second timeperiod longer than the first time period; and wirelessly transmittingdata indicative of a location of the mobile railway asset based at leastin part on the GNSS data received during the second time period fromcommunication circuitry of the sensing apparatus.
 2. The method of claim1 further comprising determining, via a controller of the sensingapparatus, the mobile railway asset event based upon data received fromat least one of a sensor and the GNSS circuitry.
 3. The method of claim1 further comprising determining, via a controller of the sensingapparatus, the mobile railway asset event in response to at least onesensor detecting a change in at least one parameter of the mobilerailway asset.
 4. The method of claim 3 wherein the at least one sensorincludes at least one of: a temperature sensor; a reed switch; apressure transducer; a strain gauge; a hall effect sensor; a temperaturesensor; a limit switch; an accelerometer; a piezo-electric sensor; amicrophone; an inductive-type sensor; and a load cell.
 5. The method ofclaim 1 further comprising receiving, via the communication circuitry ofthe sensing apparatus, a request for a location of the mobile railwayasset from an external device; and determining, via a controller of thesensing apparatus, the mobile railway asset event in response to thecommunication circuitry receiving the request from the external device.6. The method of claim 1 further comprising: determining a location ofthe mobile railway asset based at least in part on the GNSS datareceived during the first time period; and determining the mobilerailway asset event in response to the mobile railway asset locationbeing within a predetermined area.
 7. The method of claim 1 the methodfurther comprising: receiving, via the communication circuitry of thesensing apparatus, sensor data from a wireless sensor node mounted tothe mobile railway asset; and wherein wirelessly transmitting dataindicative of the location of the mobile railway asset includeswirelessly transmitting the data indicating of the location of themobile railway asset to a powered wireless gateway of a locomotive. 8.The method of claim 1 further comprising determining a location of themobile railway asset by utilizing less than all of the GNSS datareceived during the second time period.
 9. The method of claim 1 whereinpermitting the GNSS circuitry to receive GNSS data for the second timeperiod includes permitting the GNSS circuitry to receive a first portionof the GNSS data in a first portion of the second time period andpermitting the GNSS circuitry to receive a second portion of the GNSSdata in a second portion of the second time period after the firstportion, the method further including: determining a location of themobile railway asset utilizing the second portion of the GNSS data butnot the first portion of the GNSS data.
 10. The method of claim 9wherein determining the location of the mobile railway asset utilizingthe second portion of the GNSS data includes: categorizing an accuracyof the GNSS data of the second portion of the GNSS data; and determiningthe location of the mobile railway asset utilizing GNSS data having ahigher categorization of accuracy than a threshold categorization ofaccuracy.
 11. The method of claim 1 further comprising: categorizing theaccuracy of the GNSS data received during the second time period; andsetting the duration of the second time period based at least in part onthe categorized accuracy of the GNSS data received during the secondtime period.
 12. The method of claim 1 wherein inhibiting the GNSScircuitry of the apparatus from receiving GNSS data includes preventingenergization of the GNSS circuitry and permitting the GNSS circuitry toreceive GNSS data for the first and second time periods includesenergizing the GNSS circuitry using electrical energy from the limitedpower source.
 13. The method of claim 1 further comprising: at thesensing apparatus: receiving GNSS current location error data from astationary gateway; and determining a location of the mobile railwayasset based at least in part on the GNSS data received during the firsttime period and the GNSS current location error data.
 14. A stationarygateway for facilitating monitoring of the location of a mobile railwayasset in a railway connected facility, the stationary gatewaycomprising: a GNSS receiver configured to receive GNSS data fromsatellites of a GNSS; a communication interface operable to communicatewith a GNSS-enabled device of a mobile railway asset, the communicationinterface configured to facilitate communication between theGNSS-enabled device and a remote computer over a network; a processoroperably coupled to the GNSS receiver and the communication interface,the processor configured to: perform a self-survey using the GNSS datafrom the GNSS receiver; determine a self-surveyed location of thestationary gateway; determine a current location of the stationarygateway using current GNSS data received by the GNSS receiver, thecurrent location of the stationary gateway being less accurate than theself-surveyed location; determine current location error data bycomparing the current location of the stationary gateway to theself-surveyed location of the stationary gateway; and communicate thecurrent location error data to the GNSS-enabled device to facilitate theGNSS-enabled device determining a location of the mobile railway assetbased at least in part on current location error data from thestationary gateway.
 15. The stationary gateway of claim 14 wherein thecurrent location error data includes information identifying thesatellites used by the stationary gateway to calculate the currentlocation error data.
 16. The stationary gateway of claim 14 wherein thecommunication interface is configured to communicate informationindicative of the location of the mobile railway asset from theGNSS-enabled device to an external device.
 17. A method for facilitatingmonitoring of the location of a mobile railway asset in a railwayconnected facility, the system comprising: receiving, at a GNSS receiverof a stationary gateway, GNSS data from satellites of the GNSS;performing a self-survey using the gateway GNSS data; determining aself-surveyed location of the stationary gateway; determining a currentlocation of the stationary gateway using GNSS data received by the GNSSreceiver, the current location of the stationary gateway being lessaccurate than the self-surveyed location; determine current locationerror data by comparing the current location of the stationary gatewayto the self-surveyed location of the stationary gateway; andcommunicating, via a communication interface of the stationary gateway,the current location error data to the GNSS-enabled device to facilitatethe GNSS-enabled device determining a location of the mobile railwayasset based at least in part on the current location error data.
 18. Themethod of claim 17 further comprising facilitating, via thecommunication interface of the stationary gateway, a communicationbetween the GNSS-enabled device and a remote computer over a network.19. The method of claim 17 wherein the current location error dataincludes information identifying the satellites used by the stationarygateway to calculate the current location error data.
 20. An apparatusfor monitoring the location of a mobile railway asset, the apparatuscomprising: a limited power source; GNSS circuitry configured to utilizeelectrical power from the limited power source to receive GNSS data fromthe satellites of a GNSS; communication circuitry configured towirelessly receive current location error data from a stationarygateway, the current location error data determined by comparing currentlocation data of the stationary gateway to a self-surveyed location ofthe stationary gateway; and a controller operatively connected to theGNSS circuitry and the communication circuitry, the controller having: apower saving mode wherein the controller inhibits the GNSS circuitryfrom receiving GNSS data; and a location mode wherein the controllerpermits the GNSS circuitry to receive GNSS data; and the controllerconfigured to determine a location of the mobile railway asset based atlast in part on the received GNSS data and the current location errordata from the stationary gateway.
 21. The apparatus of claim 20 whereinthe communication circuitry is configured to communicate with a remotecomputer via the stationary gateway and a network.
 22. The apparatus ofclaim 20 wherein the controller is configured to enter the location modeand permit the GNSS circuitry to receive GNSS data in response to adetermination of a mobile railway asset event.
 23. The apparatus ofclaim 22 further comprising at least one sensor operatively coupled tothe controller and configured to detect a change of at least oneparameter of the mobile railway asset; and wherein the controller isconfigured to determine the mobile railway asset event in response tothe change of the at least one parameter of the mobile railway asset.24. The apparatus of claim 20 wherein the current location error dataincludes information identifying GNSS satellites used by the stationarygateway to calculate the current location error data; and wherein thecontroller is configured to determine the location of the mobile railwayasset based at last in part on the received GNSS data and the currentlocation error data from the stationary gateway calculated usingsatellites visible to both the GNSS receiver and the stationary gateway.25. The apparatus of claim 20 wherein the controller of the GNSS-enableddevice is configured to cause the communication circuitry to communicateinformation indicative of the location of the mobile railway asset to anexternal device.
 26. The apparatus of claim 20 further comprising ahousing configured to be mounted to the mobile railway asset, thehousing containing the limited power source, GNSS circuitry,communication circuitry, and the controller.
 27. A method for monitoringthe location of a mobile railway asset using a GNSS-enabled device, theGNSS-enabled device having a controller with a power saving mode whereinthe controller inhibits GNSS circuitry of the GNSS-enabled device fromreceiving GNSS data and a location mode wherein the controller permitsthe GNSS circuitry to receive GNSS data, the method comprising: at theGNSS-enabled device: receiving GNSS data from satellites of a GNSS;receiving current location error data from a stationary gateway, thecurrent location error data determined by comparing current locationdata of the stationary gateway to a self-surveyed location of thestationary gateway; and determining a location of the mobile railwayasset based at last in part on the received GNSS data and the currentlocation error data from the stationary gateway.
 28. The method of claim27 further comprising communicating, via communication circuitry of theGNSS-enabled device, with a remote computer via the stationary gatewayand a network.
 29. The method of claim 27 further comprising causing thecontroller to enter the location mode and permit the GNSS circuitry toreceive GNSS data in response to a determination of a mobile railwayasset event.
 30. The method of claim 27 wherein causing the controllerto enter the location mode and permit the GNSS circuitry to receive GNSSdata in response to the determination of a mobile railway asset eventincludes determining the mobile railway asset event in response to atleast one sensor connected to the controller detecting a change in atleast one parameter of the mobile railway asset.
 31. The method of claim27 wherein the current location error data includes informationidentifying GNSS satellites used by the stationary gateway to calculatethe current location error data; and wherein determining the location ofthe mobile railway asset based at last in part on the received GNSS dataand the current location error data from the stationary gateway includesdetermining the location of the mobile railway asset based at last inpart on the received GNSS data and the current location error data fromthe stationary gateway calculated using satellites visible to both theGNSS receiver and the stationary gateway.
 32. The method of claim 27further comprising communicating, via communication circuitry of theGNSS-enabled device and the stationary gateway, information indicativeof the location of the mobile railway asset to an external device.